High intensity pulsed light source configurations

Abstract

A high-intensity light source configuration has a long lifetime and can be modulated at a high rate. The configuration includes a movable member mounted to an actuator; a light-emitting phosphor region associated with the movable member; an input light source that illuminates the light-emitting phosphor region at a spot that is fixed relative to an emitted light output region; and a light source controller controlling the movable member actuator and the input light source. The input light source (e.g., laser) provides high-intensity input light to the illuminated spot, causing the light-emitting phosphor region to emit high-intensity output light. The light-emitting phosphor region is moved relative to the illuminated spot so as to reduce optical quenching and photobleaching, to thereby extend the life of the light source configuration. The phosphor region may emit broadband light and/or may include respective sub-regions having phosphors that emit respective peak wavelengths.

1. A light source configuration comprising:
 a movable member connected to a movable member actuator; 
 at least one light-emitting phosphor region associated with the movable member; 
 a first input light source configured to illuminate the at least one light-emitting phosphor region with input light at a first illuminated spot that is fixed relative to a first emitted light output coupling region; and 
 a light source controller operably connected to the movable member actuator and the first input light source, 
 wherein: 
 the at least one light-emitting phosphor region associated with the movable member is distributed over an area of at least 25 times a nominal area of the first emitted light output coupling region, and the at least one light-emitting phosphor region is configured to emit light in the first emitted light output coupling region in response to the input light at the first illuminated spot; and 
 the light source configuration is configured to move the at least one light-emitting phosphor region across the first illuminated spot while the at least one light-emitting phosphor region is emitting light in the first emitted light output coupling region in response to the input light at the first illuminated spot. 
 
     
     
       2. The light source configuration of  claim 1 , wherein the light source configuration is configured to move the at least one light-emitting phosphor region across the first illuminated spot at one or more speeds, while the at least one light-emitting phosphor region is emitting light in the first emitted light output coupling region in response to the input light at the first illuminated spot, including a speed of at least 2.5 m/s. 
     
     
       3. The light source configuration of  claim 2 , wherein the one or more speeds includes a speed of at least 7.5 m/s. 
     
     
       4. The light source configuration of  claim 2 , wherein the first illuminated spot has a nominal spot diameter of at most 500 microns. 
     
     
       5. The light source configuration of  claim 4 , wherein the light source configuration is configured such that the light source controller controls the first input light source to provide a spatial average of the light intensity of the first illuminated spot as high as at least 20 milliwatts per square millimeter. 
     
     
       6. The light source configuration of  claim 5 , wherein the light source configuration is configured such that the light source controller controls the first input light source to provide a spatial average of the light intensity of the first illuminated spot as high as at least 2000 milliwatts per square millimeter. 
     
     
       7. The light source configuration of  claim 6 , wherein the first illuminated spot has a nominal spot diameter of at most 100 microns. 
     
     
       8. The light source configuration of  claim 1 , wherein:
 the light source configuration is configured such that the light source controller controls the first input light source to provide at least one pulse duration; and 
 the at least one pulse duration includes a pulse duration that is at most 50 microseconds. 
 
     
     
       9. The light source configuration of  claim 1 , further comprising a first output light path optical element set, wherein:
 an entrance aperture of the first output light path optical element set is located to receive light from the first emitted light output coupling region; 
 the first output light path optical element set comprises a first output optical fiber; and 
 the entrance aperture of the first output light path optical element set comprises one of an aperture associated with a lens that transmits light to the first output optical fiber and an aperture associated with a light carrying core area at the end of the first output optical fiber. 
 
     
     
       10. The light source configuration of  claim 9 , wherein the entrance aperture of the first output light path optical element set is located at most 2.0 millimeter from the nearest portion of the at least one light-emitting phosphor region. 
     
     
       11. The light source configuration of  claim 10 , wherein the entrance aperture of the first output light path optical element set comprises the aperture associated with the light carrying core area at the end of the first output optical fiber. 
     
     
       12. The light source configuration of  claim 9 , wherein:
 the first input light source comprises a first input light generator that generates the input light and a first input light path optical element set that carries the light from the first input light generator to an exit aperture of the first input light path optical element set, the exit aperture illuminating the at least one light-emitting phosphor region at the first illuminated spot; 
 the first input light path optical element set comprises a first input optical fiber; and 
 the exit aperture of the first input light path optical element set comprises one of an aperture associated with a lens that transmits light from the first input optical fiber and an aperture associated with a light carrying core area at the end of the first input optical fiber. 
 
     
     
       13. The light source configuration of  claim 12 , wherein:
 the exit aperture of the first input light path optical element set and the entrance aperture of the first output light path optical element set are located on the same side of the at least one light-emitting phosphor region; 
 the first input optical fiber and the first output optical fiber comprise a same optical fiber segment; and 
 the exit aperture of the first input light path optical element set and the entrance aperture of the first output light path optical element set are the same aperture. 
 
     
     
       14. The light source configuration of  claim 1 , wherein:
 the first emitted light output coupling region is nominally circular and has a dimension DR; 
 the at least one light-emitting phosphor region includes a phosphor that has emission time of approximately TE; and 
 the light source configuration is configured such that the at least one light-emitting phosphor region moves across the first illuminated spot at a speed that is at most DR/TE and at least DR/(2*TE). 
 
     
     
       15. The light source configuration of  claim 1 , wherein:
 the at least one light-emitting phosphor region includes a phosphor that has emission time of approximately TE; 
 the light source configuration is configured such that the light source controller controls the first input light source to provide at least one pulse duration; and 
 the at least one pulse duration includes a pulse duration less than TE. 
 
     
     
       16. The light source configuration of  claim 1 , wherein the light source configuration is included in a host system comprising a chromatic point sensor. 
     
     
       17. The light source configuration of  claim 1 , wherein the at least one light-emitting phosphor region comprises a phosphor region that emits broadband light in response to the input light at the first illuminated spot. 
     
     
       18. The light source configuration of  claim 1 , wherein the at least one light-emitting phosphor region comprises a plurality of respective light-emitting phosphor sub-regions which emit light with different respective peak wavelengths in response to receiving the input light at the first illuminated spot. 
     
     
       19. The light source configuration of  claim 18 , wherein each respective light-emitting phosphor sub-region is distributed over an area of at least 25 times the nominal area of the first emitted light output coupling region. 
     
     
       20. The light source configuration of  claim 18 , wherein:
 the movable member actuator is operable to rotate the moveable member about a rotation axis; and 
 the respective light-emitting phosphor sub-regions comprise a first sub-region comprising an area arranged at a first radius from the rotation axis and over a first angular range AR 1  about the rotation axis, and a second sub-region comprising an area arranged at the first radius from the rotation axis and over a second angular range AR 2  about the rotation axis, such that rotation of the moveable member moves the first and second sub-regions sequentially across a location where the first illuminated spot occurs. 
 
     
     
       21. The light source configuration of  claim 18 , wherein:
 the movable member actuator is configured to rotate the moveable member about the rotation axis with an angular velocity ω; 
 the light source controller is configured to control the first input light source to provide at least one pulse duration that is less than AR 1 /ω; 
 the light source controller is configured to control the first input light source to synchronize the at least one pulse duration that is less than AR 1 /ω with the rotation of the moveable member such that when it occurs the first illuminated spot falls within the angular range AR 1 ; and 
 the light source configuration is operable to emit light having the respective peak wavelength corresponding to the first sub-region over one or more rotations of the movable member without emitting light corresponding to any other light-emitting phosphor sub-regions. 
 
     
     
       22. The light source configuration of  claim 18 , wherein:
 the movable member actuator is operable to rotate the moveable member about a rotation axis; and 
 the respective light-emitting phosphor sub-regions comprise a first sub-region comprising an area arranged at a first radius from the rotation axis and over 360 degrees about the rotation axis, and a second sub-region comprising an area arranged at a second radius from the rotation axis and over 360 degrees about the rotation axis. 
 
     
     
       23. The light source configuration of  claim 21 , wherein:
 the movable member actuator is operable to translate the movable member along a direction perpendicular to the rotation axis; and 
 translation of the moveable member along the direction perpendicular to the rotation axis moves the first and second sub-regions sequentially across the location where the first illuminated spot occurs. 
 
     
     
       24. The light source configuration of  claim 21 , further comprising:
 a second input light source connected to the light source controller and configured to illuminate the at least one light-emitting phosphor region with input light at a second illuminated spot that is fixed relative to a second emitted light output coupling region; 
 a first output light path optical element set comprising a respective entrance aperture that is located to receive light from the first emitted light output coupling region and transmit that light through an optical fiber of the first output light path optical element set; and 
 a second output light path optical element set comprising a respective entrance aperture that is located to receive light from the second emitted light output coupling region and transmit that light through an optical fiber of the second output light path optical element set, 
 wherein: 
 the light source configuration is configured such that the first illuminated spot may be positioned to coincide with the first sub-region and the first sub-region may emit light having the respective peak wavelength corresponding to the first sub-region at the same time that the second illuminated spot is positioned to coincide with the second sub-region and the second sub-region emits light having the respective peak wavelength corresponding to the second sub-region. 
 
     
     
       25. The light source configuration of  claim 24 , wherein an optical fiber of the first output light path optical element set and an optical fiber of the second output light path optical element set comprise the same optical fiber. 
     
     
       26. The light source configuration of  claim 1 , further comprising a beamsplitter and a power sensor, wherein:
 the beamsplitter is arranged to receive a portion of the light emitted from the first emitted light output coupling region in response to the input light at the first illuminated spot, and to direct a portion of the received light to the power sensor; and 
 the light source controller is configured to control the power of the input light at the first illuminated spot based on a signal provided by the power sensor. 
 
     
     
       27. The light source configuration of  claim 1 , wherein the light source configuration comprises a light gathering arrangement comprising a light gathering mirror that generally surrounds the first emitted light output coupling region and concentrates light emitted from the first emitted light output coupling region proximate to an entrance aperture of a first output light path optical element set. 
     
     
       28. The light source configuration of  claim 27 , wherein the light gathering mirror comprises an ellipsoidal mirror, and the light source configuration includes positioning with the first illuminated spot proximate to one focus of the ellipsoidal mirror and the entrance aperture of the first output light path optical element set proximate to the other focus of the ellipsoidal mirror. 
     
     
       29. The light source configuration of  claim 1 , wherein the light source configuration comprises a light gathering arrangement comprising a light gathering optical fiber arrangement comprising a plurality of optical fibers having their input ends arranged at different positions to receive light emitted along a plurality of directions from the first emitted light output coupling region. 
     
     
       30. The light source configuration of  claim 1 , further comprising a second input light source connected to the light source controller and configured to illuminate the at least one light-emitting phosphor region with input light at the first illuminated spot that is fixed relative to the first emitted light output coupling region, such that the input light from the first and second input light sources provides a combined intensity at the first illuminated spot. 
     
     
       31. The light source configuration of  claim 1 , wherein:
 the movable member actuator is operable to rotate the moveable member about a rotation axis; 
 the movable member has a maximum dimension that is at most 50 millimeters along a direction perpendicular to the rotations axis; and 
 the light source configuration is configured to move the at least one light-emitting phosphor region across the first illuminated spot at one or more speeds, while the at least one light-emitting phosphor region is emitting light in the first emitted light output coupling region in response to the input light at the first illuminated spot, including a speed of at least 2.5 m/s. 
 
     
     
       32. A method for operating a light source configuration, the light source configuration comprising a movable member connected to a movable member actuator; a at least one light-emitting phosphor region associated with the movable member; an input light source configured to illuminate the at least one light-emitting phosphor region with input light at an illuminated spot that is fixed relative to an emitted light output coupling region; and a light source controller operably connected to the movable member actuator and the input light source, the method comprising the steps of:
 providing the light source configuration, including providing a movable member configured such that the at least one light-emitting phosphor region is distributed on the movable member over an area of at least 25 times a nominal area of the emitted light output coupling region; 
 operating the light source configuration to illuminate the at least one light-emitting phosphor region with input light at the illuminated spot such that the at least one light-emitting phosphor region emits light in the emitted light output coupling region in response to the input light at the illuminated spot; and 
 operating the light source configuration to move the at least one light-emitting phosphor region across the illuminated spot while the at least one light-emitting phosphor region is emitting light in the emitted light output coupling region. 
 
     
     
       33. The method of  claim 32 , wherein operating the light source configuration to move the at least one light-emitting phosphor region across the illuminated spot comprises moving the at least one light-emitting phosphor region relative to the illuminated spot at a speed that is at least 2.5 m/s. 
     
     
       34. The method of  claim 32 , further comprising operating the movable member actuator to move the at least one light-emitting phosphor region relative to the illuminated spot such that the illuminated spot traverses a first track along the at least one light-emitting phosphor region during a first operating period of the light source configuration and such that the illuminated spot traverses a second track along the at least one light-emitting phosphor region during a second operating period of the light source configuration, wherein the second track is different than the first track. 
     
     
       35. The method of  claim 32 , wherein the light source configuration is configured such that the illuminated spot has a nominal spot diameter of at most 2.0 millimeters. 
     
     
       36. The method of  claim 32 , further comprising operating the light source configuration such that the light source controller controls the input light source to provide at least one pulse duration, and the at least one pulse duration includes a pulse duration that is at most 50 microseconds. 
     
     
       37. The method of  claim 32 , further comprising operating the light source configuration to provide light to a host system comprising a chromatic point sensor.